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authorFlorian Weimer <fweimer@redhat.com>2021-12-09 09:49:32 +0100
committerFlorian Weimer <fweimer@redhat.com>2021-12-09 09:49:32 +0100
commite3e589829d16af9f7e73c7b70f74f3c5d5003e45 (patch)
treef52c82410e4faed193d05dcf28c2586d6f83de16 /sysdeps/nptl
parent1d350aa06091211863e41169729cee1bca39f72f (diff)
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nptl: Add glibc.pthread.rseq tunable to control rseq registration
This tunable allows applications to register the rseq area instead of glibc. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com> Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Diffstat (limited to 'sysdeps/nptl')
-rw-r--r--sysdeps/nptl/dl-tls_init_tp.c11
-rw-r--r--sysdeps/nptl/dl-tunables.list6
-rw-r--r--sysdeps/nptl/internaltypes.h1
3 files changed, 17 insertions, 1 deletions
diff --git a/sysdeps/nptl/dl-tls_init_tp.c b/sysdeps/nptl/dl-tls_init_tp.c
index fedb876..b39dfbf 100644
--- a/sysdeps/nptl/dl-tls_init_tp.c
+++ b/sysdeps/nptl/dl-tls_init_tp.c
@@ -23,6 +23,9 @@
#include <tls.h>
#include <rseq-internal.h>
+#define TUNABLE_NAMESPACE pthread
+#include <dl-tunables.h>
+
#ifndef __ASSUME_SET_ROBUST_LIST
bool __nptl_set_robust_list_avail;
rtld_hidden_data_def (__nptl_set_robust_list_avail)
@@ -92,7 +95,13 @@ __tls_init_tp (void)
}
}
- rseq_register_current_thread (pd);
+ {
+ bool do_rseq = true;
+#if HAVE_TUNABLES
+ do_rseq = TUNABLE_GET (rseq, int, NULL);
+#endif
+ rseq_register_current_thread (pd, do_rseq);
+ }
/* Set initial thread's stack block from 0 up to __libc_stack_end.
It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
diff --git a/sysdeps/nptl/dl-tunables.list b/sysdeps/nptl/dl-tunables.list
index ac5d053..d24f4be 100644
--- a/sysdeps/nptl/dl-tunables.list
+++ b/sysdeps/nptl/dl-tunables.list
@@ -27,5 +27,11 @@ glibc {
type: SIZE_T
default: 41943040
}
+ rseq {
+ type: INT_32
+ minval: 0
+ maxval: 1
+ default: 1
+ }
}
}
diff --git a/sysdeps/nptl/internaltypes.h b/sysdeps/nptl/internaltypes.h
index 6032a6b..dec8c5b 100644
--- a/sysdeps/nptl/internaltypes.h
+++ b/sysdeps/nptl/internaltypes.h
@@ -48,6 +48,7 @@ struct pthread_attr
#define ATTR_FLAG_OLDATTR 0x0010
#define ATTR_FLAG_SCHED_SET 0x0020
#define ATTR_FLAG_POLICY_SET 0x0040
+#define ATTR_FLAG_DO_RSEQ 0x0080
/* Used to allocate a pthread_attr_t object which is also accessed
internally. */